Method of heating material by electricity.



W. S. FRANKLIN. METHOD OF HEATING MATERIAL BY ELECTRICITY.

APPLIOATION FILED MAR.2,1906

Patented July 29, 1913.

[mm/55555 INVENTOR 21. 9? 9 W4 )2 M,

B. FRANKLIN, OF SOUTH BETHLEHEM, PENNSYLV A NIA.

METHOD ormwrme MATERIAL BY nmc'rnrcrtrr.

, Specification 01' Letters Patent. Application fled Inch 2, 1908. Serial No. 303,328.

To all whom it may concern Be it known that I, WILLIAM S. FRANK- LIN, of South Bethlehem, in the county of Northampton, and in the State of Pennsylvania, have invented a certain new and useful Improvement in Methods of Heating Material by Electricity, and do hereby declare that the following is a full, clear, and exact description thereof reference be ng had to the accompanying drawing, in which the figure shows a furnace or apparatus which may be used in the practice of my invention.

The object ofmy invention is to enable the heating of materials by electricity which will make unnecessary the employment of carbon or metal electrodes, and, indeed, the use of any electrodes 'in direct contact with the material to be heated, and to this end my invention consists in the method substantially as hereinafter specified and claimed.

In making my invention I have availed myself of the fact that the refractory linings of clay, sand, or magnesia of the iron or metal-bound ladles or pots used in smelting operations become fairly good electrical conductors at the temperatures which ordinarily exist in the use of'such ladles or pots, it being possible to have a very considerable volume of current pass from the lining to the pot contents or melt, or vice versa, without generating an excessive amount of heat in the lining. Satisfactory results, however, cannot readily be secured by .passingthe current through so large a body or mass as constitutes the ordinary melt, and I, therefore, 'reduce the body or quantity of the melt in proportion to the volume of current, so that the temperature may be raised to the desired degree. One way of doing this is to employ two of the pots or ladles that, respectively, are the terminals of the circuit,'-the conductors, of course, being connected to the metal exterior of the pots or ladles, and I pour from one ladle to the other, thereby securing a constricted stream from one to the other, through which the current passes, and by reason of which heat is generated by the passage through it of the current. Of course, the size of the stream or jet from one pot to the other may be regulated at will by pouring more or less ra idly from one pot to the other. The material tobe heated may be delivered in a melted form into the pot from which it is to be poured, ora suitable melted slag, raised to any desired high temperature, may be placed in the pot, and the material to be heated may be introduced into this slag, with which it will flow from one pot-to the other.

Patented July 29,1913.

I, of course, do not limit myself to the employment of any particular kind of apparatus for the practice of my invention, that WhlCh I have shown and described havlng been selected merel as one arrangement by WhlCh my meth may be practiced. Thus, instead of pouring or delivering the stream into another ladleor pot, such as the ladle B, it might be delivered to, say, a

large casting having a crack or flaw in it to be'filled or repaired, the casting being connected with one of the terminals of the source of current, and the stream being directed into the crack or flaw.

Some of the uses to which my invention is applicable are the following 1. In ordinary iron foundry work it is sometimes desirable to melt a small charge of chromium or other refractory metal rearatory to its admixture to the cast 1ron 1n the large ladle. For this purpose a small amount of melted cast iron or slag may be drawn off into the ladles A and B of my 'jet furnace, heated up to any desired temperature, after which the chromium orother metal maybe added and the electric treat- .trically before being added to the steel. s

3. For the treatment of platinum or other metals which must be treated at very high temperature in the absence of carbon. In such a case, a suitable slag could bev melted in an auxiliary furnace, pouredv into the jet furnace ladles and brought to any de sired temperature The platinum or other metal to be treated could then be introduced and the electric heating continued ad 4. It can be used on a large scale ,for the' manufacture of, hi h grade steel. For Jthis purpose, it would I best to melt a suitable slag basic slag .for example) in an auxiliary rnace, pour it into the ladles A and B, both made as large as desired. W'iththis slag the jet furnace could-be gotten into operation. Then either molten cast iron or cold scrap could be introduced and the heat treatment continued until the desired composition has been reached. Then, instead of discharging the entire melt a portion could be left in the furnace ladles to start the o eration anew, and so on. a

5. y invention can be used for the'inelting of high grade glasses, the operation being once started by a melt from an auxiliary furnace. For glass melting this jet furnace would be particularly suitable, inasmuch as carbon electrodes are absolutely out of the question here, and inasmuch as the glass jet could be drawn out very long (and covered by a protecting hood) and a small current at any desired high voltage could be used.

6. And, in general, my invention can be used for the electric heating of any metallic or vitreous substance.

The advantages of my invention are, the entire absence of carbon electrodes; the possibilit of using any one of a great variety of re ractory linings for the furnace pots, an acid lining of sand, or a basic lining of lime or magnesia, or a neutral lining of refractory clay, this wide choice of linm material (which liningmaterial is virtualfv the electrode material of the furnace) making it possible to suit the electrodes of the furnace to any substance, glass or metal, that is to be treated; the heat is produced in the material that is being treated, not in an auxiliary resistance material; and in its being adapted,

even in small sizes, to the use of small cur-. rents at high voltages which, of course, means necessarily a reduction of every variety of diiliculty which can possibly be associated with the delivery of current to and the taking of current from the furnace.

The disadvantage arising'from the free radiation from the jet. where the extreme temperatures in the furnace are. reached is largely compensated by the possibility of preventing the loss of heat elsewhere; Thus,

in the ordinary electrode furnace, an enormous amount of heat is carried oif by the electrodes. Furthermore, the radiation from .the intensely heated jet may be, t o a great extent, prevented by a protective hood or I cylinder of refractory material which surrounds the 'et without touching it.

Having t us described my invention, what I claim is 1. The method of electrically heating a material, which consists in placing the same in a receptacle or holder having a metal exterior and a refractory lining, and passing the material in a stream from such recepraci m holder to a receiver these two being the terminals of a circuit'w ich includes the refractory lining and the material to be heated, the current being passed directly between'the lining and the material.

2. The method of electrically heating a material, which consists in causing the same, in a heated condition, to pass ina stream from a holder or receptacle having a refractory lining to a receiver having a similar lining, these two being, respectively, the terminals of an electrical circuit.

1 3.. The method of electrically heating. a 80 material, which consists in causing the same, in a heated condition, to pass :in a stream from a holder or receptacle having a refractory lining and a metal exterior to a receiver havingza similar lining and exterior, these two being, respectively, the terminals of an eledtrical circuit, the conductors of the circuit being attached to said metal exteriors.

4. The method of electrically heating a material having a high melting point, "which consists in forming a stream of a material having a low melting point, having mixed therewith particles of the first mentioned material and causing an electric current to pass through said stream.

5. The method of electrically heating a material having a high melting point, which consists in mixing said material with a body of melted material having a low melting point, forming a stream of said mixed materials between two receptacles, and including said receptacles in series in an electric circuit.

material, which consists in assing the material from one point to anot er, in a stream,

the stream being included in or forming part of an electric circuit and preventing the radiation of heat from the'streani;

- In-testimony that I claim the foregoing I have hereunto set myhand.

WILLIAM S. FRANKLIN.

Witnesses: I

THOMAS ZQFRANKILIN, HENRY KRAUSKOPF.

6. The method of electrically heating a 

